title: Serum levels of vitamin E forms and risk of cognitive impairment in a Finnish cohort of older adults.
abstract: BACKGROUND
  Vitamin E includes eight natural antioxidant compounds (four tocopherols and four tocotrienols), but α-tocopherol has been the main focus of investigation in studies of cognitive impairment and Alzheimer's disease.
  
  
  OBJECTIVE
  To investigate the association between serum levels of tocopherols and tocotrienols, markers of vitamin E oxidative/nitrosative damage (α-tocopherylquinone, 5-nitro-γ-tocopherol) and incidence of cognitive impairment in a population-based study.
  
  
  METHODS
  A sample of 140 non-cognitively impaired elderly subjects derived from the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study was followed-up for 8years to detect cognitive impairment, defined as development of mild cognitive impairment (MCI) or Alzheimer's dementia. The association between baseline serum vitamin E and cognitive impairment was analyzed with multiple logistic regression after adjusting for several confounders.
  
  
  RESULTS
  The risk of cognitive impairment was lower in subjects in the middle tertile of the γ-tocopherol/cholesterol ratio than in those in the lowest tertile: the multiadjusted odds ratio (OR) with 95% confidence interval (CI) was 0.27 (0.10-0.78). Higher incidence of cognitive impairment was found in the middle [OR (95% CI): 3.41 (1.29-9.06)] and highest [OR (95% CI): 2.89 (1.05-7.97)] tertiles of the 5-NO2-γ-tocopherol/γ-tocopherol ratio. Analyses of absolute serum levels of vitamin E showed lower risk of cognitive impairment in subjects with higher levels of γ-tocopherol, β-tocotrienol, and total tocotrienols.
  
  
  CONCLUSIONS
  Elevated levels of tocopherol and tocotrienol forms are associated with reduced risk of cognitive impairment in older adults. The association is modulated by concurrent cholesterol concentration. Various vitamin E forms might play a role in cognitive impairment, and their evaluation can provide a more accurate measure of vitamin E status in humans.
authors.affiliation: Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Stockholm, Sweden; Institute of Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy. Electronic address: francesca.mangialasche@ki.se.
authors.forename: Francesca
authors.initials: F
authors.lastname: Mangialasche
authors.forename: Alina
authors.initials: A
authors.lastname: Solomon
authors.forename: Ingemar
authors.initials: I
authors.lastname: Kåreholt
authors.forename: Babak
authors.initials: B
authors.lastname: Hooshmand
authors.forename: Roberta
authors.initials: R
authors.lastname: Cecchetti
authors.forename: Laura
authors.initials: L
authors.lastname: Fratiglioni
authors.forename: Hilkka
authors.initials: H
authors.lastname: Soininen
authors.forename: Tiina
authors.initials: T
authors.lastname: Laatikainen
authors.forename: Patrizia
authors.initials: P
authors.lastname: Mecocci
authors.forename: Miia
authors.initials: M
authors.lastname: Kivipelto
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000097:blood* / Q000523:psychology*; D000544:Alzheimer Disease / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D002784:Cholesterol / Q000097:blood; D003071:Cognition; D060825:Cognitive Dysfunction / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D018450:Disease Progression; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D018384:Oxidative Stress; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D024505:Tocopherols / Q000097:blood; D024508:Tocotrienols / Q000097:blood; D014810:Vitamin E / Q000097:blood*
chemical_list: D015415:Biomarkers; D024508:Tocotrienols; D014810:Vitamin E; D002784:Cholesterol; D024505:Tocopherols
keywords: 5-NO(2)-γ-tocopherol; 5-nitro-γ-tocopherol; AD; APOE; Alzheimer's disease; Apolipoprotein E; BMI; Body mass index; CAIDE; CDR; CERAD; CI; CNS; CV; Cardiovascular Risk Factors, Aging, and Dementia study; Central nervous system; Clinical Dementia Rating Scale; Coefficient of variation; Cognitive impairment; Confidence interval; Consortium to Establish a Registry for Alzheimer's Disease; DSM-IV; Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; HDL; HPLC; High Performance Liquid Chromatography; High-density lipoprotein; LDL; Low-density lipoprotein; MCI; MMSE; MRI; Magnetic resonance imaging; Mini-Mental State Examination; NINCDS-ADRDA; NS; National Institute of Neurologic and Communicative Disorders and Stroke–Alzheimer's Disease and Related Disorders Association; Nitrosative stress; OR; OS; Odds ratio; Oxidative stress; Oxidative/nitrosative stress; RNS; Reactive nitrogen species; SD; Standard deviation; Tocopherol; Tocotrienol; Vitamin E; mild cognitive impairment; α-Tocopherylquinone; αTQ